Photoelectric conversion device and x-ray imaging device

ABSTRACT

A photoelectric conversion device includes a photoelectric conversion area in which photoelectric conversion elements each including a first electrode, a second electrode, and a photoelectric conversion layer, provided between the first electrode and the second electrode, that contains a semiconductor material are provided in a matrix and a guard ring surrounding a periphery of the photoelectric conversion area in a form of a frame. The guard ring has an intermediate layer containing the same semiconductor material as the photoelectric conversion layer.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Provisional Application No.63/158,551 the content to which is hereby incorporated by reference intothis application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a photoelectric conversion device andan X-ray imaging device.

2. Description of the Related Art

For example, International Publication No. 2013/088975 discloses asolid-state imaging device provided with a guard ring surrounding theperiphery of a functional area in which pixels are provided in a matrix.In International Publication No. 2013/088975, the guard ring is formedusing a metal layer that is at the same layer as a metal layer used inthe pixels. According to International Publication No. 2013/088975,forming the guard ring using the metal layer makes it possible toinhibit moisture or gas from entering the functional area from outsidethe guard ring.

SUMMARY OF THE INVENTION

Note here that the functional area is surrounded by a frame areaprovided with routed wires routed using a metal material forelectrically connecting the pixels with terminals or other componentsprovided in the frame area. The routed wires are formed using a metallayer that is at the same layer as the metal layer used in the pixels.

The guard ring described in PTL 1 is provided in such a way as tosurround the periphery of the functional area. Therefore, for anelectrical connection between the pixels in the functional area and theterminals in the frame area through the routed wires, there is a need tocause the routed wires to cross the guard ring in plan view.

However, since the guard ring is formed using the metal layer that is atthe same layer as the metal layer used in the pixels, the guard ring isat the same layer as the metal layer used in the routed wires. For thisreason, in order to cause the routed wires to cross the guard ring,there is a need to pattern, at a different layer from the metal layerused in the pixels, a metal layer that serves as another new routedwires. This makes it take a lot of trouble to form the routed wires.

To address this problem, an embodiment of the present disclosure has asan object to provide a photoelectric conversion device and an X-rayimaging device that have a structure that makes crossing of a guard ringand a wire easy.

According to an aspect of the present disclosure, there is provided aphotoelectric conversion device including: a photoelectric conversionarea in which photoelectric conversion elements each including a firstelectrode, a second electrode, and a photoelectric conversion layer,provided between the first electrode and the second electrode, thatcontains a semiconductor material are provided in a matrix; and a guardring surrounding a periphery of the photoelectric conversion area in aform of a frame, wherein the guard ring has an intermediate layercontaining the same semiconductor material as the photoelectricconversion layer.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view schematically showing a configuration of anX-ray imaging device according to an embodiment.

FIG. 2 is plan view schematically representing a configuration of aphotoelectric conversion device according to the embodiment.

FIG. 3 is a diagram representing the appearance of a routed wire (wire)in the photoelectric conversion device according to the embodiment.

FIG. 4 is a plan view schematically showing a configuration of aphotoelectric conversion device according to Modification 1 of theembodiment.

FIG. 5 is a diagram showing an example of a configuration of aprotection circuit element provided in each of first and secondprotection circuit sections shown in FIG. 4.

FIG. 6 is a cross-sectional view schematically representing aconfiguration of a pixel in the photoelectric conversion deviceaccording to the embodiment.

FIG. 7 is a cross-sectional view schematically representing aconfiguration of components around a guard ring in the photoelectricconversion device according to the embodiment.

FIG. 8 is a cross-sectional view schematically representing aconfiguration of components around a terminal in the photoelectricconversion device according to the embodiment.

FIG. 9 is a cross-sectional view schematically representing aconfiguration of a photoelectric conversion device according to acomparative example.

FIG. 10 is a cross-sectional view schematically representing aconfiguration of a pixel in a photoelectric conversion device accordingto Modification 2 of the embodiment.

FIG. 11 is a cross-sectional view schematically representing aconfiguration of components around a guard ring in the photoelectricconversion device according to Modification 2 of the embodiment shown inFIG. 10.

FIG. 12 is a cross-sectional view schematically representing aconfiguration of a pixel in a photoelectric conversion device accordingto Modification 3 of the embodiment.

FIG. 13 is a cross-sectional view schematically representing aconfiguration of components around a guard ring in the photoelectricconversion device according to Modification 3 of the embodiment shown inFIG. 12.

DETAILED DESCRIPTION OF THE INVENTION Embodiment

FIG. 1 is a schematic view schematically showing a configuration of anX-ray imaging device 1 including a photoelectric conversion device 10according to an embodiment. The X-ray imaging device 1 takes an image ofa subject S with X-rays. The X-ray imaging device 1 is used, forexample, in an X-ray fluoroscopic apparatus, an X-ray CT apparatus, orother apparatuses. The X-ray imaging device 1 of the present embodimenthas an X-ray source 2, a scintillator 3, and the photoelectricconversion device 10.

The X-ray source 2 irradiates the subject S with X-rays. The X-raysfalling on the subject S pass through the subject S and fall on thescintillator 3 provided over the photoelectric conversion device 10. TheX-rays falling on the scintillator 3 are converted into fluorescence(hereinafter referred to as “scintillation light”) that then falls onthe photoelectric conversion device 10. The scintillation light fallingon the photoelectric conversion device 10 is converted by theafter-mentioned photoelectric conversion element 40 provided in thephotoelectric conversion device 10 into electric charge corresponding tothe amount of light, and is read out as an electrical signal. Then, thephotoelectric conversion device 10 generates an X-ray image on the basisof the electrical signal.

FIG. 2 is plan view schematically representing a configuration of thephotoelectric conversion device 10 according to the embodiment. Thephotoelectric conversion device 10 includes a substrate 20, a gate wire(wire) 13GW, a data wire 14DW, a bias wire 14A, a pixel PX, a guard ring40GR, a terminal TM, or other components provided on the substrate 20.The pixel PX includes a TFT 30 and a photoelectric conversion element40. Further, the photoelectric conversion device 10 has a controlsection 50.

The control section 50 controls operation of each of the components ofthe photoelectric conversion device 10. The control section 50 includesa driver connected to the TFTs (thin-film transistors) 30 and thephotoelectric conversion element 40. The driver includes a signalreadout section 12 and a gate control section 11 that are provided onthe substrate 20.

The substrate 20 is constituted, for example, by a material such asglass. A central area of the substrate 20 is a photoelectric conversionarea A1 in which a plurality of the pixels PX serving as a plurality ofimaging elements are provided in a matrix, and a peripheral area of thesubstrate 20 that surrounds the photoelectric conversion area A1 is aframe area A2. The photoelectric conversion area A1 is an area thattakes an image of the subject S.

The frame area A2 is an area in which various types of driving circuit(such as the gate control section 11 and the signal readout section 12)for driving the plurality of pixels PX, various types of wire, the guardring 40GR, or other components are provided.

Each pixel PX includes a TFT 30 and a photoelectric conversion element40. That is, a plurality of the TFTs 30 and a plurality of thephotoelectric conversion elements 40 are provided in a matrix in thephotoelectric conversion area A1.

For example, the photoelectric conversion element 40 has its anodeconnected to the bias wire 14A, and has its cathode connected to a drainelectrode of the TFT 30. The TFT 30 has its drain electrode connected tothe cathode of the photoelectric conversion element 40, has its sourceelectrode connected to the data wire 14DW, and has its gate electrodeconnected to the gate wire 13GW.

A plurality of the gate wires 13GW and a plurality of the data wires14DW are provided in such a way as to cross each other in thephotoelectric conversion area A1. For example, each of the plurality ofgate wires 13GW is connected to the gate electrodes of a plurality ofthe TFTs 30, is extended across the guard ring 40GR in plan view in theframe area A2, and has an end connected to the gate control section 11.Each of the plurality of data wires 14DW is connected to the sourceelectrodes of a plurality of the TFTs 30, is extended across the guardring 40GR in plan view in the frame area A2, and has an end connected tothe signal readout section 12.

For example, the plurality of gate wires 13GW are extended in a firstdirection (up-down direction as seen from the front of the surface ofpaper), and the gate control section 11, which is connected to theplurality of gate wires 13GW, is provided along a side of thephotoelectric conversion area A1 extended in a second direction(right-left direction as seen from the front of the surface of paper)orthogonal to the first direction. For example, the plurality of datawires 14DW are extended in the second direction (right-left direction asseen from the front of the surface of paper), and the signal readoutsection 12, which is connected to the plurality of data wires 14DW, isprovided along a side of the photoelectric conversion area A1 extendedin the first direction orthogonal to the second direction.

The guard ring 40GR is provided in the frame area A2, and is provided inthe form of a frame to surround the periphery of the photoelectricconversion area A1. The guard ring 40GR is formed using a material thathardly allows passage of moisture or gas. This allows the guard ring40GR to inhibit moisture or gas from entering the photoelectricconversion area A1 from outside the guard ring 40GR through a resinlayer, stacked on the substrate 20, that allows easier entry of moistureand gas than an inorganic insulating layer.

A plurality of the terminals TM are provided along ends of the substrate20 in the frame area A2, and are electrically connected to a pluralityof terminals or other components of an external driving circuit (notillustrated). The plurality of terminals TM include a plurality ofterminals TM1 and a plurality of terminals TM2 that are placed side byside along ends of the substrate 20 that are different from each other.For example, in the example shown in FIG. 2, the plurality of terminalsTM1 are placed side by side in the second direction (right-leftdirection as seen from the front of the surface of paper) along an endextended along the gate control section 11. Further, in the exampleshown in FIG. 2, the plurality of terminals TM2 are placed side by sidein the first direction (up-down direction as seen from the front of thesurface of paper) along an end extended along the signal readout section12.

FIG. 3 is a diagram representing the appearance of a routed wire (wire)W1 in the photoelectric conversion device 10 according to theembodiment.

Each of a plurality of the routed wires W1 has its first end connectedprovided in the photoelectric conversion area A1, and has its second endconnected to a corresponding one of the plurality of terminals TM. Forexample, the plurality of routed wires W1 include a routed wire W11having its second end connected to a terminal TM1 and a routed wire W12having its second end connected to a terminal TM2.

The routed wire W1 has its first end provided in the photoelectricconversion area A1 and electrically connected to any of electrodes (e.g.the gate electrode, the source electrode, or the drain electrode)constituting the TFT 30, electrodes (e.g. a first electrode 41 or asecond electrode 43) constituting the photoelectric conversion element40, or various types of wire (e.g. the gate wire 13GW, the data wire14DW, or the bias wire 14A) in the photoelectric conversion area A1.

For example, each of the plurality of routed wires W1 is formed at thesame layer using the same material as a metal layer (e.g. the gateelectrode, the source electrode, or the drain electrode) constitutingthe TFT 30 (as will be described in detail later with reference to FIGS.7 and 8 or other drawings). The plurality of routed wires W1 each extendfrom the first end to the second end in such a way as to cross the guardring 40GR in plan view.

For example, each of a plurality of the routed wires W11 has its firstend provided in the photoelectric conversion area A1, has its second endconnected to a terminal TM1, crosses the guard ring 40GR in plan viewfrom the first end to the second end, and is extended in the firstdirection (up-down direction as seen from the front of the surface ofpaper in FIG. 3).

For example, each of a plurality of the routed wires W12 has its firstend provided in the photoelectric conversion area A1, has its second endconnected to a terminal TM2, crosses the guard ring 40GR from the firstend to the second end, and is extended in the second direction(right-left direction as seen from the front of the surface of paper inFIG. 3).

In the present embodiment, in order to make it easy for a wire, such asthe gate wire 13GW and the routed wire W1, formed at the same layerusing the same material as a metal layer (e.g. the gate electrode, thesource electrodes, and the drain electrodes) used in the formation of,particularly, the TFT 30 in the pixel PX and the guard ring 40GR tocross each other in plan view, the guard ring 40GR has an intermediatelayer, formed at a different layer from the metal layer used in theformation of the TFT 30, that contains the same semiconductor materialas a photoelectric conversion layer included in the photoelectricconversion element 40. It should be noted that the guard ring 40GR willbe described in detail later with reference to FIG. 7 or other drawings.

As shown in FIGS. 1 and 2, upon irradiation with X-rays from the X-raysource 2, the control section 50 applies a predetermined voltage (biasvoltage) to the bias wire 14A. The X-rays from the X-ray source 2 passthrough the subject S and fall on the scintillator 3. The X-rays fallingon the scintillator 3 are converted into scintillation light that thenfalls on the photoelectric conversion device 10. The scintillation lightfalling on the photoelectric conversion device 10 is converted by thephotoelectric conversion element 40 into electric charge correspondingto the amount of light. A signal corresponding to the electric chargegenerated by the photoelectric conversion element 40 is read out by thesignal readout section 12 through the data wire 14DW when the TFT 30 isin an ON state in response to a gate voltage outputted from the gatecontrol section 11 via the gate wire 13GW. Then, the control section 50generates an X-ray image corresponding to the signal thus read out.

FIG. 4 is a plan view schematically showing a configuration of aphotoelectric conversion device 10 according to Modification 1 of theembodiment. As shown in FIG. 4, the photoelectric conversion device 10may be a so-called COF (chip-on-film) structure in which the controller50 is provided not on a glass substrate but on a film. In the exampleshown in FIG. 4, the photoelectric conversion device 10 has a firstcircuit board C1 obtained by mounting the gate control section 11 on afirst film F1 and a second circuit board C2 obtained by mounting thesignal readout section 12 on a second film F2.

The first film F1 and the second film F2 are for example flexible filmscontaining resin materials such as polyimide. The gate control section11 is electrically connected via the first film F1 to a plurality of thegate wires 13GW routed in the frame area A2. The signal readout section12 is electrically connected via the second film F2 to a plurality ofthe data wires 14DW routed in the frame area A2. The first film F1 maybe electrically connected to the plurality of terminals TM1. Further,the second film F2 may be electrically connected to the plurality ofterminals TM2.

Further, as shown in FIG. 4, for example, the photoelectric conversiondevice 10 may have a first protection circuit section B1 and a secondprotection circuit section B2 in each of which protection circuitelements are provided in an array. The first protection circuit sectionB1 is provided, for example, between the first circuit board C1 and thephotoelectric conversion area A1. The second protection circuit sectionB2 is provided, for example, between the second circuit board C2 and thephotoelectric conversion area A1.

FIG. 5 is a diagram showing an example of a configuration of aprotection circuit element provided in each of the first and secondprotection circuit sections B1 and B2 shown in FIG. 4. As shown in FIG.5, a plurality of protection circuit elements μl are provided in each ofthe first and second protection circuit sections B1 and B2.

In the first protection circuit section B1, each of the protectioncircuit elements μl for example has its first end connected to a gatewire 13GW extending from the gate control section 11 to thephotoelectric conversion area A1, and has its second end connected to aground (GND) terminal having a reference potential. This allows theprotection circuit element μl to inhibit a large voltage generated, forexample, by static electricity from flowing to the gate wire 13GW.

Further, in the second protection circuit section B2, each of theprotection circuit elements μl for example has its first end connectedto a data wire 14DW extending from the signal readout section 12 to thephotoelectric conversion area A1, and has its second end connected to aground (GND) terminal having a reference potential. This allows theprotection circuit element μl to inhibit a large voltage generated, forexample, by static electricity from flowing to the data wire 14DW.

It should be noted that each of the plurality of protection circuitelements μl may be provided in such a way as to be electricallyconnected to a corresponding one of the routed wires W1 (see FIG. 3)routed in the frame area A2.

FIG. 6 is a cross-sectional view schematically representing aconfiguration of the pixel PX in the photoelectric conversion device 10according to the embodiment. The TFT 30 includes a gate electrode 31GE,a semiconductor layer 32, a source electrode 33SE, and a drain electrode33DE. The gate electrode 31GE, the source electrode 33SE, and the drainelectrode 33DE are each a metal layer used in the formation of the TFT30.

The gate electrode 31GE and the gate wire 13GW (see FIG. 2) are providedover the substrate 20. The gate electrode 31GE is electrically connectedto the gate wire 13GW. For example, the gate electrode 31GE and the gatewire 13GW are formed at the same layer in the same step using the samematerial as each other.

The gate electrode 31GE and the gate wire 13GW are for example eachconfigured such that a metal layer containing tantalum nitride (TaN) isstacked as a lower layer and a metal film containing tungsten (W) isstacked as an upper layer. Alternatively, the gate electrode 31GE andthe gate wire 13GW may for example be each configured such that a metallayer containing titanium (Ti) is stacked as a lower layer and a metalfilm containing copper (Cu) is stacked as an upper layer. Alternatively,the gate electrode 31GE and the gate wire 13GW may for example be eachconfigured such that a metal layer containing aluminum (Al) is stackedas a lower layer and a metal film containing molybdenum nitride (MoN) isstacked as an upper layer. In the present embodiment, the film thicknessof the metal layer serving as the lower layer is approximately 300 nm,and the film thickness of the metal layer serving as the upper layer isapproximately 30 nm. Note, however, that the materials and filmthicknesses of the gate electrode 31GE and the gate wire 13GW are notlimited to the foregoing.

A gate insulating layer 21 is provided over the substrate 20, and coversthe gate electrode 31GE and the gate wire 13GW (see FIG. 2). The gateinsulating layer 21 is constituted, for example, by an inorganicinsulating layer containing silicon oxide (SiO_(x)), silicon nitride(SiN_(x)), silicon oxynitride (SiO_(x)N_(y)) (x>y), silicon nitroxide(SiN_(x)O_(y)) (x>y), or other materials. The gate insulating layer 21of the present embodiment is configured such that an inorganicinsulating layer containing silicon nitride (SiN_(x)) is stacked as alower layer and an inorganic insulating layer containing silicon oxide(SiO_(x)) is stacked as an upper layer. In the present embodiment, thefilm thickness of the inorganic insulating layer serving as the lowerlayer is approximately 325 nm, and the film thickness of the inorganicinsulating layer serving as the upper layer is approximately 10 nm.Note, however, that the materials and film thicknesses of the gateinsulating layer 21 are not limited to the foregoing.

The semiconductor layer 32 is provided over the gate insulating layer 21in such a way as to overlap the gate electrode 31GE via the gateinsulating layer 21. For example, the semiconductor layer 32 isconstituted by an oxide semiconductor. Usable examples of the oxidesemiconductor include InGaO₃(ZnO)₅, magnesium zinc oxide(Mg_(x)Zn_(y)O), cadmium zinc oxide (Cd_(x)Zn_(y)O), cadmium oxide(CdO), and an amorphous oxide semiconductor containing predeterminedproportions of indium (In), gallium (Ga), and zinc (Zn). Thesemiconductor layer 32 of the present embodiment is configured such thatan oxide semiconductor film containing an amorphous oxide semiconductorcontaining predetermined proportions of indium (In), gallium (Ga), andzinc (Zn) is stacked as a lower layer and an amorphous oxidesemiconductor film containing predetermined proportions of indium (In),gallium (Ga), and zinc (Zn) is stacked as an upper layer. In the presentembodiment, the film thickness of the oxide semiconductor film servingas the lower layer is approximately 70 nm, and the film thickness of theoxide semiconductor film serving as the upper layer is approximately 25nm. Note, however, that the materials and film thicknesses of thesemiconductor layer 32 are not limited to the foregoing.

The source electrode 33SE and the drain electrode 33DE are formed at thesame layer in the same step using the same material as each other.Specifically, the source electrode 33SE and the drain electrode 33DE areprovided over the gate insulating layer 21 in such a way as to makecontact with parts of the semiconductor layer 32. The source electrode33SE and the drain electrode 33DE of the present embodiment are eachconfigured, for example, to have a three-layer structure in which ametal film containing titanium (Ti), a metal film containing aluminum(Al), and a metal film containing titanium (Ti) are stacked in thisorder from the substrate 20 side (lower layer side). In the presentembodiment, the film thicknesses of these three layers are approximately30 nm, approximately 400 nm, and approximately 50 nm in this order fromthe substrate 20 side. Note, however, that the materials and filmthicknesses of the source electrode 33SE and the drain electrode 33DEare not limited to the foregoing.

A first insulating layer 22 is provided over the gate insulating layer21, and covers the semiconductor layer 32, the source electrode 33SE,and the drain electrode 33DE. The first insulating layer 22 is forexample an inorganic insulating layer containing an inorganic insulatingmaterial such as silicon oxide (SiO_(x)), silicon nitride (SiN_(x)),silicon oxynitride (SiO_(x)N_(y)) (x>y), or silicon nitroxide(SiN_(x)O_(y)) (x>y). The first insulating layer 22 of the presentembodiment contains, for example, silicon oxide (SiO_(x)) and has a filmthickness of approximately 500 nm. Note, however, that the material andfilm thickness of the first insulating layer 22 are not limited to theforegoing. The first insulating layer 22 has an opening in an areaoverlapping the source electrode 33SE in top view, and also has anopening in an area overlapping the drain electrode 33DE in top view.

Thus, the TFT 30 of the present embodiment is of a bottom-gate typehaving a gate electrode 31GE provided at a layer that is closer to thesubstrate 20 side (lower layer side) than the semiconductor layer 32.Note, however, the TFT 30 may be of a top-gate type having a gateelectrode 31GE provided at a layer that is farther (toward an upperlayer side) away from the substrate 20 side than the semiconductor layer32 or a double-gate type having gate electrodes 31GE at both a layerthat is closer to the substrate 20 side (lower layer side) than thesemiconductor layer 32 and a layer that is farther (toward an upperlayer side) away from the substrate 20 side than the semiconductor layer32.

It should be noted that the semiconductor layer 32, the source electrode33SE, and the drain electrode 33DE may be formed at the same layer inthe same step using the same semiconductor material as each other.Specifically, the semiconductor layer 32, the source electrode 33SE, andthe drain electrode 33DE may for example be formed as a single entity byan identical oxide semiconductor material. In this case, the sourceelectrode 33SE and the drain electrode 33DE are formed by being at leastpartially subjected to a resistance-lowering process. Thus, the sourceelectrode 33SE and the drain electrode 33DE may be formed aslow-resistance semiconductors whose conductivity is higher than that ofthe semiconductor layer 32.

The photoelectric conversion element 40 is stacked on the substrate 20.The photoelectric conversion element 40 includes a first electrode 41, asecond electrode 43, and a photoelectric conversion layer 42, providedbetween the first electrode 41 and the second electrode 43, thatcontains a semiconductor material.

The first electrode 41 is provided over the first insulating layer 22,and is electrically connected to the drain electrode 33DE via a contacthole formed in the first insulating layer 22.

Further, a metal layer 41A formed at the same layer over the firstinsulating layer 22 in the same step using the same material as thefirst electrode 41. The metal layer 41A is provided so that part of themetal layer 41A overlaps the source electrode 33SE via the firstinsulating layer 22, and is electrically connected to the sourceelectrode 33SE via a contact hole formed in the first insulating layer22.

The first electrode 41 and the metal layer 41A are each configured, forexample, to have a three-layer structure in which a metal filmcontaining titanium (Ti), a metal film containing aluminum (Al), and ametal film containing titanium (Ti) are stacked in this order from thesubstrate 20 side (lower layer side). In the present embodiment, thefilm thicknesses of these three layers are approximately 30 nm,approximately 300 nm, and approximately 100 nm in this order from thesubstrate 20 side. Note, however, that the materials and filmthicknesses of the first electrode 41 and the metal layer 41A are notlimited to the foregoing.

A second insulating layer 23 is provided over the first insulating layer22, and covers the first electrode 41 and the metal layer 41A. Thesecond insulating layer 23 covers ends of the first electrode 41, andhas an opening over a central portion of the first electrode 41.

The second insulating layer 23 is for example an inorganic insulatinglayer containing an inorganic insulating material such as silicon oxide(SiO_(x)), silicon nitride (SiN_(x)), silicon oxynitride (SiO_(x)N_(y))(x>y), or silicon nitroxide (SiN_(x)O_(y)) (x>y). The second insulatinglayer 23 of the present embodiment contains, for example, siliconnitride (SiN_(x)) and has a film thickness of approximately 300 nm.Note, however, that the material and film thickness of the secondinsulating layer 23 are not limited to the foregoing. The secondinsulating layer 23 has an opening in an area overlapping the metallayer 41A in plan view, and also has an opening in an area overlappingthe first electrode 41 in plan view.

The photoelectric conversion layer 42 includes an n-type semiconductorlayer 42A1, an i-type semiconductor layer 42A2, and a p-typesemiconductor layer 42A3, staked in this order from the substrate 20side, each of which contains a semiconductor material. The n-typesemiconductor layer 42A1 is provided over portions of the secondinsulating layer 23 covering the ends of the first electrode 41 and overthe first electrode 41 via the opening of the second insulating layer 23formed over the central portion of the first electrode 41.

Note here that in a case where the second insulating layer does notcover the ends of the first electrode and the photoelectric conversionlayer has its ends in direct contact with an upper surface of the firstelectrode, the upper surface of the first electrode is etched when thephotoelectric conversion layer is patterned by dry etching or otherprocesses, with the result that the upper surface of the first electrodeadheres as adherents to side walls of the photoelectric conversionlayer. The adherents having thus adhered to the side walls of thephotoelectric conversion layer undesirably form a leak path of anelectric current, thus inviting an increase in leak current of thephotoelectric conversion layer.

Meanwhile, in the photoelectric conversion device 10 according to thepresent embodiment, the first electrode 41 has its ends covered with thesecond insulating layer 23. Moreover, the photoelectric conversion layer42 is electrically connected to the first electrode 41 via the openingof the second insulating layer 23 formed over the central portion of thefirst electrode 41. That is, the photoelectric conversion layer 42 hasits ends provided over the first electrode 41 via the second insulatinglayer 23.

This makes it possible to, when the first electrode 41 is formed, thesecond insulating layer 23 is formed, and then the photoelectricconversion layer 42 is patterned, for example, by etching such as dryetching, inhibit the first electrode 41, which is at a lower layer thanthe photoelectric conversion layer 42, from being etched. This makes itpossible to inhibit a leak path from being formed in the photoelectricconversion layer 42 by adherents adhering when the photoelectricconversion layer 42 is patterned. As a result, the photoelectricconversion device 10 makes it possible to obtain a high-definition X-rayimage.

The n-type semiconductor layer 42A1 contains amorphous silicon doped,for example, with an n-type impurity such as phosphorus (P). The filmthickness of the n-type semiconductor layer 42A1 of the presentembodiment is approximately 10 nm. Note, however, that the material andfilm thickness of the n-type semiconductor layer 42A1 are not limited tothe foregoing.

The i-type semiconductor layer 42A2 is provided over the n-typesemiconductor layer 42A1, and is in contact with the n-typesemiconductor layer 42A1. The i-type semiconductor layer 42A2 containsi-type amorphous silicon. That is, the i-type semiconductor layer 42A2contains intrinsic amorphous silicon. The film thickness of the i-typesemiconductor layer 42A2 of the present embodiment is approximately 1000nm. Note, however, that the material and film thickness of the i-typesemiconductor layer 42A2 are not limited to the foregoing.

The p-type semiconductor layer 42A3 is provided over the i-typesemiconductor layer 42A2, and is in contact with the i-typesemiconductor layer 42A2. The p-type semiconductor layer 42A3 containsamorphous silicon doped, for example, with a p-type impurity such asboron (B). The film thickness of the p-type semiconductor layer 42A3 ofthe present embodiment is approximately 10 nm. Note, however, that thematerial and film thickness of the p-type semiconductor layer 42A3 arenot limited to the foregoing.

The second electrode 43 is provided over the p-type semiconductor layer42A3. The second electrode 43 is formed, for example, by a transparentconductive material such as ITO (indium tin oxide). The film thicknessof the second electrode 43 is approximately 50 nm. Note, however, thatthe material and film thickness of the second electrode 43 are notlimited to the foregoing.

A third insulating layer 24 is provided over the photoelectricconversion element 40. The third insulating layer 24 covers the secondelectrode 43, and is provided over the p-type semiconductor layer 42A3.The third insulating layer 24 is for example an inorganic insulatinglayer containing an inorganic insulating material such as silicon oxide(SiO_(x)), silicon nitride (SiN_(x)), silicon oxynitride (SiO_(x)N_(y))(x>y), or silicon nitroxide (SiN_(x)O_(y)) (x>y). The third insulatinglayer 24 of the present embodiment contains, for example, siliconnitride (SiN_(x)) and has a film thickness of approximately 50 nm. Note,however, that the material and film thickness of the third insulatinglayer 24 are not limited to the foregoing.

A fourth insulating layer 25 is provided over the second insulatinglayer 23, and covers the photoelectric conversion element 40 and thethird insulating layer 24. The fourth insulating layer 25 is for examplean inorganic insulating layer containing an inorganic insulatingmaterial such as silicon oxide (SiO_(x)), silicon nitride (SiN_(x)),silicon oxynitride (SiO_(x)N_(y)) (x>y), or silicon nitroxide(SiN_(x)O_(y)) (x>y). The fourth insulating layer 25 of the presentembodiment contains, for example, silicon nitride (SiN_(x)) and has afilm thickness of approximately 400 nm. Note, however, that the materialand film thickness of the fourth insulating layer 25 are not limited tothe foregoing.

A fifth insulating layer 26 is provided over the fourth insulating layer25. The fifth insulating layer 26 is formed, for example, usingtransparent resin such as acrylic resin, siloxane resin, or polyimideresin. The film thickness of the fifth insulating layer 26 of thepresent embodiment is approximately 2.5 μm. Note, however, that thematerial and film thickness of the fifth insulating layer 26 are notlimited to the foregoing.

It should be noted that since the fifth insulating layer 26 of thepresent embodiment is a resin layer formed using a resin material, itcan be made greater in film thickness than an inorganic insulating layerformed using an inorganic insulating material. For this reason, thefifth insulating layer 26 also functions as a planarizing layer thatcovers and thereby planarizes irregularities on the substrate 20 formedby the TFT 30 and the photoelectric conversion element 40. Theplanarization of the irregularities formed by the TFT 30 and thephotoelectric conversion element 40 makes it possible to inhibit thescintillation light from being diffusely reflected due to theirregularities and obtain a photoelectric conversion device 10 thatgives a higher-definition X-ray image.

The data wire 14DW and the bias wire 14A are formed at the same layerover the fifth insulating layer 26 in the same step using the samematerial as each other. The data wire 14DW is electrically connected tothe metal layer 41A via a contact hole formed in the fifth insulatinglayer 26, the fourth insulating layer 25, and the second insulatinglayer 23. That is, the data wire 14DW is electrically connected to thesource electrode 33SE via the metal layer 41A. The bias wire 14A iselectrically connected to the second electrode 43 via a contact holeformed in the fifth insulating layer 26, the fourth insulating layer 25,and the third insulating layer 24.

The data wire 14DW and the bias wire 14A are each configured, forexample, to have a four-layer structure in which a metal film containingtitanium (Ti), a metal film containing aluminum (Al), a metal filmcontaining titanium (Ti), and a transparent conductive layer containinga transparent conductive material such as ITO are stacked in this orderfrom the substrate 20 side (lower layer side). In the presentembodiment, the film thicknesses of these four layers are approximately60 nm, approximately 600 nm, approximately 50 nm, and approximately 100nm in this order from the substrate 20 side. Note, however, that thematerials, film thicknesses, stack structures of the data wire 14DW andthe bias wire 14A are not limited to the foregoing.

A sixth insulating layer 27 is provided over the fifth insulating layer26, and covers the data wire 14DW and the bias wire 14A. The sixthinsulating layer 27 is for example an inorganic insulating layercontaining an inorganic insulating material such as silicon oxide(SiO_(x)), silicon nitride (SiN_(x)), silicon oxynitride (SiO_(x)N_(y))(x>y), or silicon nitroxide (SiN_(x)O_(y)) (x>y). The sixth insulatinglayer 27 of the present embodiment contains, for example, siliconnitride (SiN_(x)) and has a film thickness of approximately 450 nm.Note, however, that the material and film thickness of the sixthinsulating layer 27 are not limited to the foregoing.

A seventh insulating layer 28 is provided over the sixth insulatinglayer 27. The seventh insulating layer 28 is formed, for example, usingtransparent resin such as acrylic resin, siloxane resin, or polyimideresin. The film thickness of the seventh insulating layer 28 of thepresent embodiment is approximately 3.0 μm. Note, however, that thematerial and film thickness of the seventh insulating layer 28 are notlimited to the foregoing.

It should be noted that since the seventh insulating layer 28 of thepresent embodiment is a resin layer formed using a resin material, itcan be made greater in film thickness than an inorganic insulating layerformed using an inorganic insulating material. For this reason, theseventh insulating layer 28 also functions as a planarizing layer thatcovers and thereby planarizes irregularities formed by the TFT 30, thephotoelectric conversion element 40, the data wire 14DW, the bias wire14A, or other components. The planarization of the irregularities formedby the TFT 30, the photoelectric conversion element 40, the data wire14DW, the bias wire 14A, or other components makes it possible toinhibit the scintillation light from being diffusely reflected due tothe irregularities and obtain a photoelectric conversion device 10 thatgives a higher-definition X-ray image.

That is, in the photoelectric conversion device 10, which is providedwith a plurality of resin layers (in the present embodiment, two layers,namely the fifth insulating layer 26 and the seventh insulating layer28) that can be made greater in film thickness than an inorganicinsulating layer, a surface of the photoelectric conversion area A1 canbe more planarized than in a configuration provided with no plurality ofresin layers. This makes it possible to more inhibit the diffusereflection of the scintillation light due to the irregularities on thesurface of the photoelectric conversion area. Therefore, thephotoelectric conversion device 10 makes it possible tophotoelectrically convert the scintillation light with high definitionthrough each pixel PX. As a result, the photoelectric conversion device10 makes it possible to obtain a higher-definition X-ray image.

FIG. 7 is a cross-sectional view schematically representing aconfiguration of components around the guard ring 40GR in thephotoelectric conversion device 10 according to the embodiment. Theconfiguration of the guard ring 40GR and components around the guardring 40GR is described with reference to FIGS. 6 and 7.

For example, the guard ring 40GR has a first layer 41GR, an intermediatelayer 42GR, and a second layer 43GR that are stacked in this order froma lower layer on the substrate 20 side to an upper layer. Theintermediate layer 42GR is provided between the first layer 41GR and thesecond layer 43GR. The first layer 41GR is at a lower layer than theintermediate layer 42GR, and the second layer 43GR is stacked at ahigher layer than the intermediate layer 42GR.

The first layer 41GR is provided over the first insulating layer 22, andcontains the same electrical conducting material as the first electrode41 and the metal layer 41A. That is, the first layer 41GR is formed atthe same layer in the same step using the same material as the firstelectrode 41 and the metal layer 41A. The second insulating layer 23 isprovided over the first insulating layer 22, and covers ends of thefirst layer 41GR.

The intermediate layer 42GR contains the same semiconductor material asthe photoelectric conversion layer 42. For example, the intermediatelayer 42GR has a first intermediate layer 42GRA1, a second intermediatelayer 42GRA2, and a third intermediate layer 42GRA3 that are stacked inthis order.

The first intermediate layer 42GRA1 is provided over portions of thesecond insulating layer 23 covering the ends of the first layer 41GR andover the first layer 41GR. The first intermediate layer 42GRA1 containsthe same semiconductor material as the n-type semiconductor layer 42A1(see FIG. 6). That is, the first intermediate layer 42GRA1 is formed atthe same layer in the same step using the same material as the n-typesemiconductor layer 42A1 (see FIG. 6).

The second intermediate layer 42GRA2 is provided over the firstintermediate layer 42GRA1. The second intermediate layer 42GRA2 containsthe same semiconductor material as the i-type semiconductor layer 42A2(see FIG. 6). That is, the second intermediate layer 42GRA2 is formed atthe same layer in the same step using the same material as the i-typesemiconductor layer 42A2.

The third intermediate layer 42GRA3 is provided over the secondintermediate layer 42GRA2. The third intermediate layer 42GRA3 containsthe same semiconductor material as the p-type semiconductor layer 42A3(see FIG. 6). That is, the third intermediate layer 42GRA3 is formed atthe same layer in the same step using the same material as the p-typesemiconductor layer 42A3.

The second layer 43GR is provided over the third intermediate layer42GRA3, and contains the same electrical conducting material as thesecond electrode 43 (see FIG. 6). That is, the second layer 43GR isformed at the same layer in the same step using the same material as thesecond electrode 43. A third insulating layer 24GR is provided over thethird intermediate layer 42GRA3, and covers the second layer 43GR. Thethird insulating layer 24GR is formed at the same layer in the same stepusing the same material as the third insulating layer 24 (see FIG. 6).

The fourth insulating layer 25 is provided over the second insulatinglayer 23, and covers the intermediate layer 42GR and the thirdinsulating layer 24GR.

The fifth insulating layer 26 is provided over the fourth insulatinglayer 25, and has a groove portion 26 a, formed in a portion thereofoverlapping the guard ring 40GR, that extends along the guard ring 40GR.The groove portion 26 a is formed in the shape of a frame along theguard ring 40 GR (see FIG. 3) in plan view. Thus, the fifth insulatinglayer 26, which is formed using a resin material, is divided by thegroove portion 26 a and the guard ring 40GR into an inner area 26 bsurrounded by the guard ring 40GR and an outer area 26 c outside theguard ring 40GR. A bottom surface of the interior of the groove portion26 a is a surface of the fourth insulating layer 25.

The sixth insulating layer 27 is provided over the fifth insulatinglayer 26, and is also provided in the groove portion 26 a. That is, thesixth insulating layer 27 is provided in such a way as to cover asurface of the inner area 26 b and a surface of the outer area 26 c and,furthermore, covers side surfaces of the interior of the groove portion26 a and a portion of the surface of the fourth insulating layer 25serving as the bottom surface of the interior of the groove portion 26a.

Further, the sixth insulating layer 27 has formed therein an opening 27a through which moisture, gas, or other substances in the fifthinsulating layer 26 is let out to the seventh insulating layer 28, whichis at a higher layer than the sixth insulating layer 27. The opening 27a is formed on a portion of a surface of the fifth insulating layer 26serving as a surface of the outer area 26 c outside the guard ring 40GR.In other words, the guard ring 40GR is provided inside (closer to thephotoelectric conversion area A1 than) the opening 27 a formed in thesixth insulating layer 27.

The seventh insulating layer 28 is provided over the sixth insulatinglayer 27, and is in contact with the surface of the outer area 26 c ofthe fifth insulating layer 26 via the opening 27 a formed in the sixthinsulating layer 27. Further, the seventh insulating layer 28 is alsoprovided in the groove portion 26. That is, the seventh insulating layer28, which is formed using a resin material and can therefore be madegreater in film thickness than an inorganic insulating layer, canplanarize irregularities on a surface of the sixth insulating layer 27formed by the opening 27 a, the groove portion 26 a, or other componentsformed in the sixth insulating layer 27.

As indicated by arrows Z1, for example, moisture or gas may enter theouter area 26 c of the fifth insulating layer 26, which is a resinlayer, via the opening 27 a from within the seventh insulating layer 28,which is a resin layer that allows easier entry of moisture and gas thanan inorganic insulating layer, or moisture or gas may enter the outerarea 26 c of the fifth insulating layer 26, which is a resin layer, inan in-plane direction. However, as indicated by an arrow Z2, providingthe guard ring 40GR, which is formed by a material that hardly allowspassage of moisture, makes it possible to prevent moisture or gas in theouter area 26C of the fifth insulating layer 26 from entering the innerarea 26 b of the fifth insulating layer 26 inside the guard ring 40GR.

This makes it possible to prevent moisture or gas from being transmittedto the photoelectric conversion area A1 through the inside of the innerarea 26 b of the fifth insulating layer 26. This results in making itpossible to obtain a highly-reliable photoelectrically-converted signal.

Further, the routed wire W1 is provided in such a way as to cross theguard ring 40GR. The routed wire W1 is provided at a different layerfrom the guard ring 40GR. As an example, the routed wire W1,particularly the routed wire W12, is described here.

For example, the routed wire W12 contains the same electrical conductingmaterial as the source electrode 33SE (FIG. 6) and the drain electrode33DE. That is, the routed wire W12 is formed at the same layer in thesame step using the same material as the source electrode 33SE (FIG. 6)and the drain electrode 33DE.

FIG. 8 is a cross-sectional view schematically representing aconfiguration of components around a terminal TM2 in the photoelectricconversion device 10 according to the embodiment. The routed wire W12 isdescribed with reference to FIGS. 3 to 8.

The routed wire W12 is provided over the gate insulating layer 21, andis covered with the first insulating layer 22. That is, for example, therouted wire W12 is provided at a lower layer than the guard ring 40GR,passes under the guard ring 40GR, and crosses the guard ring 40GR.

The routed wire W12 has its first end provided in the photoelectricconversion area A1 and electrically connected to any of electrodes (e.g.the gate electrode, the source electrode, or the drain electrode)constituting the TFT 30, electrodes (e.g. the first electrode 41 or thesecond electrode 43) constituting the photoelectric conversion element40, or various types of wire (e.g. the gate wire 13GW, the data wire14DW, or the bias wire 14A) in the photoelectric conversion area A1.

As shown in FIG. 8, the routed wire W12 has its second end connected tothe terminal TM2. For example, the terminal TM2 is formed at the samelayer in the same step using the same material as the routed wire W12,the source electrode 33SE, and the drain electrode 33DE. The terminalTM2 is provided over the gate insulating layer 21, and has its surfaceexposed through an opening H1 formed in the first insulating layer 22,the second insulating layer 23, the fourth insulating layer 25, thefifth insulating layer 26, the sixth insulating layer 27, and theseventh insulating layer 28 over the terminal TM2. This configures theterminal TM2 to be able to make an electrical contact with a terminal ofan external driving circuit or other devices.

Although not illustrated in cross-section, the routed wire W11 (see FIG.3) and the plurality of terminals TM1 are for example formed at the samelayer in the same step using the same material as the gate electrode31GE (see FIG. 6). The routed wire W11 is for example formed over thesubstrate 20, and is covered with the gate insulating layer 21. Theplurality of terminals TM1 (see FIG. 3) are for example formed over thesubstrate 20, and have their surfaces exposed through openings formed inthe gate insulating layer 21, the first insulating layer 22, the secondinsulating layer 23, the fourth insulating layer 25, the fifthinsulating layer 26, the sixth insulating layer 27, and the seventhinsulating layer 28 over the terminals TM1. This configures theterminals TM1 to be able to make electrical contacts with terminals ofan external driving circuit or other devices.

FIG. 9 is a cross-sectional view schematically representing aconfiguration of a photoelectric conversion device 110 according to acomparative example. The photoelectric conversion device 110 has aplurality of pixels PX100 provided in a photoelectric conversion area.

Each pixel PX100 has a TFT 130 and a photoelectric conversion element140 that are provided over a substrate 120.

The TFT 130 has a gate electrode 131GE, a source electrode 133SE, and adrain electrode 133DE.

The gate electrode 131GE of the TFT 130 is provided over the substrate120, and a gate insulating layer 121 is provided over a first surface ofthe substrate 120, and covers the gate electrode 131GE. A semiconductorlayer 132 of the TFT 130 is provided over the gate insulating layer 121,and furthermore, the drain electrode 133DE and source electrode 133SE ofthe TFT 130 are provided over the gate insulating layer 121 in such away as to partially overlap the semiconductor layer 132. A firstinsulating layer 122 is provided over the gate insulating layer 121, andcovers the TFT 130.

The photoelectric conversion element 140 has a first electrode 141, aphotoelectric conversion layer 142, and a second electrode 143.

The first electrode 141 is provided over the first insulating layer 122,serves as a lower electrode of the photoelectric conversion element 140,and is electrically connected to the drain electrode 133DE via a contacthole formed in the first insulating layer 122. A second insulating layer123 is provided over the first insulating layer 122, and covers ends ofthe first electrode 141.

The photoelectric conversion layer 142 is provided over the firstelectrode 141, and has an n-type semiconductor layer 142A1, an i-typesemiconductor layer 142A2, and a p-type semiconductor layer 142A3 thatare stacked in this order from a lower layer to an upper layer. Thesecond electrode 143 is provided over the photoelectric conversion layer142, and serves as an upper electrode. A third insulating layer 124 isprovided over the second electrode 143. Moreover, a fourth insulatinglayer 125 is provided over the second insulating layer 123, and coversthe third insulating layer 124 and the photoelectric conversion element140.

Further, the photoelectric conversion device 110 has a guard ring 140GRprovided over the substrate 120 in such a way as to surround theperiphery of the photoelectric conversion area. The guard ring 140GR isconfigured such that a first layer 131GR and a second layer 133GR arestacked in this order over the substrate 120.

The first layer 131GR is formed at the same layer by the same step usingthe same material as the gate electrode 131GE. The second layer 133GR isformed at the same layer by the same step using the same material as thesource electrode 133SE and the drain electrode 133DE.

Thus, in the photoelectric conversion device 110, the first layer 131GRof the guard ring 140GR is formed at the same layer as the gateelectrode 131GE, and the second layer 133GR is formed at the same layeras the source electrode 133SE. For this reason, a wire formed at thesame layer as the gate electrode 131GE or the source electrode 133SEcannot cross the guard ring 140GR. For this reason, for the formation ofa gate wire and a routed wire, there is a need to separately pattern ametal layer at a different layer from the gate electrode 131GE and thesource electrode 133SE.

In the photoelectric conversion device 110, a fifth insulating layer 101is provided on a second surface of the substrate 120 reverse (opposite)to the first surface, and a routed wire W100 is provided over the fifthinsulating layer 101 by patterning another metal layer that is differentfrom a metal layer for forming the TFT 130. Moreover, a sixth insulatinglayer 102 is provided over the fifth insulating layer 105, and coversthe routed wire W100.

The routed wire W100 is electrically connected to the source electrode133SE via a contact hole H100 formed in the fifth insulating layer 101,the substrate 120, and the gate insulating layer 121. Moreover, therouted wire W100 passes under the guard ring 140GR and crosses the guardring 140GR.

Thus, in the photoelectric conversion device 110, the guard ring 140GRhas a first layer 131GR and a second layer 133GR that are formed at thesame layer by the same step using the same material as the metal layerused in the TFT 130. For this reason, in order to form the routed wireW100 so that the routed wire W100 crosses the guard ring 140GR, a metallayer that is different from the metal layer used in the TFT 130 needsto be reconnected by being patterned on the second surface of thesubstrate 120 opposite to the first surface on which the guard ring140GR is provided.

This increases the number of steps and takes a lot of trouble.

Meanwhile, as described with reference to FIGS. 6 and 7, in thephotoelectric conversion device 10 according to the present embodiment,the guard ring 40GR that the photoelectric conversion device 10according to the present embodiment thus includes has the intermediatelayer 42GR, which contains the same semiconductor material as thephotoelectric conversion layer 42.

This allows the guard ring 40GR to be crossed by a wire (e.g. at leastany of the gate wire 13GW (see FIGS. 2 and 4), the data wire 14DW (seeFIGS. 2 and 4), the routed wire W11 (see FIG. 3), and the routed wireW12 (see FIGS. 3, 7, and 8)) formed at the same layer by the same stepusing the same material as a metal layer (i.e. the gate electrode 31GE,the source electrode 33SE, or the drain electrode 33DE) used in the TFT30 of the pixel PX. This makes it unnecessary to, unlike in thephotoelectric conversion device 110 according to the comparativeexample, reconnect from the metal layer used in the TFT 30 and therebyform a wire so that the wire crosses the guard ring 40GR, and makes iteasy to cross the guard ring 40GR. Thus, the photoelectric conversiondevice 10 has a structure that makes crossing of the guard ring 40GR anda wire (e.g. the gate wire 13GW (see FIG. 2), the routed wire W11 (seeFIG. 3), and the routed wire W12 (see FIGS. 3, 7, and 8)) easy. Thismakes it possible to hold down an increase in the number of steps.

Thus, at least any of the wires (e.g. the gate wire 13GW (see FIG. 2),the data wire 14DW (see FIGS. 2 and 4), the routed wire W11 (see FIG.3), and the routed wire W12 (see FIGS. 3, 7, and 8)) that thephotoelectric conversion device 10 includes extends from the first endto the second end in such a way as to cross the guard ring 40GR. Forthis reason, even if the guard ring 40GR is provided in such a way as tosurround the periphery of the photoelectric conversion area A1, a signalfrom any of the various types of driving circuit provided in the framearea A2 can be outputted to the pixel PX provided in the photoelectricconversion area A1 via a wire (e.g. any of the gate wire 13GW (see FIG.2), the data wire 14DW (see FIGS. 2 and 4), the routed wire W11 (seeFIG. 3), and the routed wire W12 (see FIGS. 3, 7, and 8)) crossing theguard ring 40GR, or a signal outputted from the pixel PX can beoutputted to an external circuit via the wire.

Further, as shown in FIGS. 6 and 7, for example, the guard ring 40GRhas, in addition to the intermediate layer 42GR, the first layer 41GRprovided at a lower layer than the intermediate layer 42GR and thesecond layer 43GR provided at a higher layer than the intermediate layer42GR.

The first layer 41GR is an electrically-conductive layer containing thesame electrical conducting material as the first electrode 41, and istherefore a layer that hardly allows passage of moisture or gas. Thefirst layer 41GR is formed at the same layer by the same step using thesame material as the first electrode 41.

Further, the second layer 43GR is an electrically-conductive layercontaining the same electrical conducting material as the secondelectrode 43, and is therefore a layer that hardly allows passage ofmoisture or gas. The second layer 43GR is formed at the same layer bythe same step using the same material as the second electrode 43.

Thus, the guard ring 40GR, which has the first layer 41GR and the secondlayer 43GR in addition to the intermediate layer 42GR, can be madegreater in film thickness than a guard ring having only an intermediatelayer. This makes it possible to fill in a depression formed by thegroove portion 26 a and planarize a (photosensitive) surface of thephotoelectric conversion device 10 (that receives the scintillationlight). This makes it possible to photoelectrically convert thescintillation light with high definition through each pixel PX andobtain a higher-definition X-ray image.

Alternatively, the guard ring 40GR may have only either the first layer41GR or the second layer 43GR in addition to the intermediate layer42GR. That is, the guard ring 40GR needs only have at least either thefirst layer 41GR or the second layer 43GR in addition to theintermediate layer 42GR. This too makes it possible to fill in thedepression formed by the groove portion 26 a and planarize the(photosensitive) surface of the photoelectric conversion device 10 (thatreceives the scintillation light). This too makes it possible tophotoelectrically convert the scintillation light with high definitionthrough each pixel PX and obtain a higher-definition X-ray image.

The intermediate layer 42GR of the guard ring 40GR is configured suchthat a first intermediate layer 42GRA1, a second intermediate layer42GRA2, and a third intermediate layer 42GRA3 are provided in this orderfrom a lower layer to an upper layer.

The first intermediate layer 42GRA1 contains the same semiconductormaterial as the n-type semiconductor layer 42A1 of the photoelectricconversion layer 42, and is formed at the same layer in the same step asthe n-type semiconductor layer 42A1. The second intermediate layer42GRA2 contains the same semiconductor material as the i-typesemiconductor layer 42A2 of the photoelectric conversion layer 42, andis formed at the same layer in the same step as the i-type semiconductorlayer 42A2. The third intermediate layer 42GRA3 contains the samesemiconductor material as the p-type semiconductor layer 42A3 of thephotoelectric conversion layer 42, and is formed at the same layer inthe same step as the p-type semiconductor layer 42A3.

This allows the intermediate layer 42GR to be formed by the same step asthe photoelectric conversion layer 42. This makes it unnecessary toincrease the number of separate steps to form the intermediate layer42GR, making it possible to inhibit the number of steps from increasingdue to the formation of the intermediate layer 42GR.

FIG. 10 is a cross-sectional view schematically representing aconfiguration of a pixel PX in a photoelectric conversion device 10according to Modification 2 of the embodiment. As shown in FIG. 10, thephotoelectric conversion device 10 may include an eighth insulatinglayer (planarizing layer, resin insulating layer) 29 between the firstinsulating layer 22 and the second insulating layer 23.

The eighth insulating layer 29 is provided over the first insulatinglayer 22. Moreover, the eighth insulating layer 29 covers the TFT 30 viathe first insulating layer 22, and has formed on a surface thereof thefirst electrode 41, the metal layer 41A, and the second insulating layer23, which covers the first electrode 41 and the metal layer 41A.

The first electrode 41 is electrically connected to either the drainelectrode 33DE or the source electrode 33SE (in the example shown inFIG. 10, the drain electrode 33DE) via a contact hole formed in theeighth insulating layer 29 and the first insulating layer 22.

The metal layer 41A is electrically connected to either the drainelectrode 33DE or the source electrode 33SE (in the example shown inFIG. 10, the source electrode 33SE) via a contact hole formed in theeighth insulating layer 29 and the first insulating layer 22.

The eighth insulating layer 29 is formed, for example, using aninsulative resin material containing transparent resin such as acrylicresin, siloxane resin, or polyimide resin. The film thickness of theeighth insulating layer 29 of the present embodiment is approximately2.5 μm. Note, however, that the material and film thickness of theeighth insulating layer 29 are not limited to the foregoing.

Since the eighth insulating layer 29 is a resin layer formed using aresin material, it can be made greater in film thickness than aninorganic insulating layer formed using an inorganic insulatingmaterial. For this reason, the eighth insulating layer 29 can functionas a planarizing layer that covers and thereby planarizes irregularitieson the substrate 20 formed by the TFT 30.

By thus providing the eighth insulating layer 29, which is formed usinga resin material that can be made greater in film thickness than aninorganic insulating layer, between the first electrode 41 and thesource electrode 33SE and between the first electrode 41 and the drainelectrode 33DE, the photoelectric conversion element 40, which includesthe first electrode 41, can be provided so as to overlap the TFT 30 viathe eighth insulating layer 29. This makes it possible to make theoccupied area of the photoelectric conversion layer 42 per pixel PXlarger than in a case where a photoelectric conversion element and a TFTdo not overlap each other. This makes it possible to bring aboutimprovement in sensitivity to the scintillation light per pixel PX andobtain a photoelectric conversion device 10 that gives ahigher-definition X-ray image.

FIG. 11 is a cross-sectional view schematically representing aconfiguration of components around a guard ring 40GR in thephotoelectric conversion device 10 according to Modification 2 of theembodiment shown in FIG. 10. As shown in FIG. 11, in the photoelectricconversion device 10 according to Modification 2, the eighth insulatinglayer 29 is provided over the first insulating layer 22. Moreover, thefirst layer 41GR and the second insulating layer 23 are provided overthe eighth insulating layer 29. Thus, the eighth insulating layer (resininsulating layer) 29 formed by a resin layer containing an insulativeresin material is formed at a crossing of the guard ring 40GR and therouted wire W1 (routed wire W12) and between the guard ring 40GR and therouted wire W1 (routed wire W12). This makes it possible to place theguard ring 40GR and the routed wire W1 (routed wire W12) at a longerdistance from each other at the crossing of the guard ring 40GR and therouted wire W1 (routed wire W12) than in a case where no resin layer isprovided between the guard ring 40GR and the routed wire W1 (routed wireW12).

That is, providing the eighth insulating layer 29, which contains aninsulative resin material than can be made greater in film thicknessthan an inorganic insulating layer, between the guard ring 40 and therouted wire W1 makes it possible to reduce a capacitance that is formedat the crossing of the guard ring 40 and the routed wire W1 (routed wireW12). This makes it possible to obtain a photoelectric conversion device10 that is driven at a higher speed and that consumes less electricity.

FIG. 12 is a cross-sectional view schematically representing aconfiguration of a pixel PX in a photoelectric conversion device 10according to Modification 3 of the embodiment. As shown in FIG. 12, inthe photoelectric conversion device 10, an intermediateelectrically-conductive layer 44 may be provided between the firstelectrode 41 and the photoelectric conversion layer 42. The exampleshown in FIG. 12 is a configuration in which the photoelectricconversion device 10 shown in FIG. 10 is further provided with theintermediate electrically-conductive layer 44. It should be noted thatthe eighth insulating layer 29 may be omitted from the configuration ofthe photoelectric conversion device 10.

The intermediate electrically-conductive layer 44 is provided over thefirst electrode 41 and over the second insulating layer 23 provided overthe ends of the first electrode 41. Moreover, the n-type semiconductorlayer 42A1 of the photoelectric conversion layer 42 is provided over theintermediate electrically-conductive layer 44. The intermediateelectrically-conductive layer 44 contains, for example, titanium (Ti).For example, the film thickness of the intermediateelectrically-conductive layer 44 is approximately 30 nm. Note, however,that the material and film thickness of the intermediateelectrically-conductive layer 44 are not limited to the foregoing.

Note here that electric charge may accumulate in areas of the secondinsulating layer 23 (i.e. areas indicated by dashed lines C1 in FIG. 12)provided over the ends of the first electrode 41.

Moreover, as shown in FIG. 12, the intermediate electrically-conductivelayer 44 is provided over the first electrode 41 and between the firstelectrode 41 and the photoelectric conversion layer 42. Moreover, theintermediate electrically-conductive layer 44 is also provided in such away as to cover the second insulating layer 23 provided over the ends ofthe first electrode 41. This makes it possible to cause electric chargetrying to accumulate in the second insulating layer 23 over the ends ofthe first electrode 41 to migrate to the photoelectric conversion layer42 via the intermediate electrically-conductive layer 44 and the firstelectrode 41. This makes it possible to achieve more efficientphotoelectric conversion through the photoelectric conversion layer 42,resulting in making it possible to obtain a photoelectric conversiondevice 10 that is superior in afterimage characteristics and that givesa higher-definition X-ray image.

FIG. 13 is a cross-sectional view schematically representing aconfiguration of components around a guard ring 40GR in thephotoelectric conversion device 10 according to Modification 3 of theembodiment shown in FIG. 12. As shown in FIG. 13, in the photoelectricconversion device 10 according to Modification 3, the guard ring 40GRhas a third layer 44GR provided between the first layer 41GR and theintermediate layer 42GR.

The third layer 44GR is provided over the first layer 41GR and over thesecond insulating layer 23 over the ends of the first layer 41GR, andthe first intermediate layer 42GRA1 of the intermediate layer 42GR isprovided over the third layer 44GR. The third layer 44GR contains thesame electrical conducting material as the intermediateelectrically-conductive layer 44 (see FIG. 12). That is, the third layer44GR is formed at the same layer in the same step using the samematerial as the intermediate electrically-conductive layer 44.

The guard ring 40GR shown in FIG. 13 can be made greater in filmthickness than in a case where the intermediate electrically-conductivelayer 44 is not provided. The guard ring 40GR thus made greater in filmthickness makes it possible to more planarize irregularities on asurface of the sixth insulating layer 27 formed by the groove portion 26a. This makes it possible to inhibit the scintillation light from beingdiffusely reflected due to the irregularities, resulting in making itpossible to obtain a photoelectric conversion device 10 that gives ahigher-definition X-ray image.

It should be noted that elements having appeared in the aforementionedembodiment or modifications may be appropriately combined unless acontradiction arises.

What is claimed is:
 1. A photoelectric conversion device comprising: aphotoelectric conversion area in which photoelectric conversion elementseach including a first electrode, a second electrode, and aphotoelectric conversion layer, provided between the first electrode andthe second electrode, that contains a semiconductor material areprovided in a matrix; and a guard ring surrounding a periphery of thephotoelectric conversion area in a form of a frame, wherein the guardring has an intermediate layer containing the same semiconductormaterial as the photoelectric conversion layer.
 2. The photoelectricconversion device according to claim 1, wherein the guard ring has atleast one electrically-conductive layer, stacked at a lower layer or ahigher layer than the intermediate layer, that contains the sameelectrical conducting material as at least either the first electrode orthe second electrode.
 3. The photoelectric conversion device accordingto claim 2, wherein the at least one electrically-conductive layercomprises a plurality of electrically-conductive layers, the pluralityof electrically-conductive layers include a first layer containing thesame electrical conducting material as the first electrode and a secondlayer containing the same electrical conducting material as the secondelectrode, and the intermediate layer is provided between the firstlayer and the second layer.
 4. The photoelectric conversion deviceaccording to claim 1, wherein the photoelectric conversion layer is astructure in which an n-type semiconductor layer, an i-typesemiconductor layer, and a p-type semiconductor layer are stacked, andthe intermediate layer of the guard ring is a structure in which a firstintermediate layer containing the same semiconductor material as then-type semiconductor layer, a second intermediate layer containing thesame semiconductor material as the i-type semiconductor layer, and athird intermediate layer containing the same semiconductor material asthe p-type semiconductor layer are stacked.
 5. The photoelectricconversion device according to claim 1, further comprising: a TFTprovided in the photoelectric conversion area and electrically connectedto a corresponding one of the photoelectric conversion elements; and awire formed using a material that is identical to a metal layerconstituting the TFT, wherein the wire extends from a first end to asecond end in such a way as to cross the guard ring.
 6. Thephotoelectric conversion device according to claim 1, furthercomprising: TFTs, provided in a matrix in the photoelectric conversionarea, each of which has a drain electrode, a source electrode, and agate electrode; and a resin insulating layer covering the TFTs andhaving a surface provided with the first electrode, wherein the firstelectrode is connected to at least either the drain electrode or thesource electrode via a contact hole formed in the resin insulatinglayer.
 7. The photoelectric conversion device according to claim 1,further comprising a resin insulating layer, provided at a crossing ofthe guard ring and the wire and between the guard ring and the wire,that contains an insulative resin material.
 8. The photoelectricconversion device according to claim 1, further comprising anintermediate electrically-conductive layer provided over the firstelectrode and between the first electrode and the photoelectricconversion layer.
 9. An X-ray imaging device comprising: thephotoelectric conversion device according to claim 1; and ascintillator, provided over the photoelectric conversion device, thatemits light according to X-rays falling thereon.